(Click on the pictures to enlarge)

Calibrating the first layer:

Sharing some results achived while calibrating again the printing of the very first layer on the bed. After several testings, my method was create an object large enough to cover a reasonable surface and thin enough to make the printer make a single pass (print only the first layer). That said, the object is a parallelepiped with 50mm (width) x 50mm (lenght) x 0.2mm (height).

TestPlain50x50.stl

Adjustment should be made by:

Control > Motion > Probe Z

This value sets the noozle offset. The smaller the number (in fact, negative values) closer is the noozle to the bed.

Don't forget to save value to memory with:

Control > Store Settings

Noozle too High:

• The filament does not adhere each other.
• The printing does not adhere to the bed.
• Bad printing quality. Lots of defects.

Noozle too Low:

• Pressure against the bed is too high. It is harder to remove the finished printing because it adheres too hard.
• Since the noozle is too close to the bed, few space is left so extruder motor slips while injecting the filament.
• Noozle becomes too low and it scratches already printed areas. See images below.

Noozle correct:

• Printing adhere as expected to the bed.
• Result is smooth and uniform.

Comparison: